Microbial Barrier Testing of Novel Composite Dressings

The objective of this study was to evaluate the microbial barrier properties of two novel bioelectric composite dressings (CD). We studied the dressings after seven days of simulated use with simulated wound fluid solution using a modified DIN (Deutsches Institut fur Normung E.V.) standard test method 58953-6 for determination of germ integrity in the presence of moisture and air.

The test is designed to determine if a product provides microbial barrier properties after a 24-hour period of contact exposure. The microbial barrier properties were determined for eight pathogens: Enterococcus faecalis, MRSA, Staphylococcus epidermidis, Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Candida albicans, and Aspergillus brasiliensis. Exposed the air-facing side of treated and perforated articles to ~1 x 107 CFU/ml of wound pathogens, while the skin contact-facing side was in contact with appropriate agar plate and assessed for microbial barrier properties using DIN 58953-6 “Pass” or “Fail” method after a 24-hour contact time.

The positive and sterility controls of the test articles were performed. Each control article was manually perforated using a sterile perforation tool. Results showed no growth of the eight pathogens on the agar plates after 24-hour incubation. However, the positive controls had growth for all pathogens tested. According to DIM 58953-6 analysis of Germ Proofness, the two CDs demonstrated microbial barrier properties. These bioelectric CDs have been previously demonstrated to effectively kill bacteria at the wound contact surface, reducing the risk of infection. In this study, we showed effective microbial barrier properties to external pathogens, strengthening their promise as an infection control measure for wounds.

Our team developed a modified standard which may be an effective tool for evaluating the antimicrobial barrier properties of wound dressings.